The present disclosure generally relates to a sample rack handling unit and, in particular, to a sample rack handling unit comprising a rack onload section for loading one or more sample racks. It also relates to an analytical instrument comprising such a sample rack handling unit and to a method of handling sample racks.
Different types of sample handling units have been developed for various analytical instruments. Such sample handling units are used to load sample racks holding sample containers, such as sample tubes containing analytical samples to be analyzed, into an instrument and for taking the racks out of the instrument after having been analyzed. Several sample handling units comprise an onload section wherein sample racks are queued before entering into a processing section. In the processing section, operations are performed with the sample tubes such as aspiration of sample from the sample tubes. Sample racks are then transported further to an offload section wherein sample racks are queued before being taken out from the sample handling unit.
There are systems, which comprise buffer sections and enable random access to the racks and/or sample tubes in the racks contained in such a buffer. Others comprise robotic arms and grippers to pick and transport sample racks between different sections. Some comprise a dedicated onload section for sample racks holding sample tubes with urgent samples having priority in the queue. Such systems are however large, bulky, complex and expensive, therefore suitable only for larger high-throughput instruments. Smaller instruments and/or instruments with smaller throughput normally integrate simpler and more compact sample rack handling units. These typically comprise a single and linear transportation path. This means that if a sample has to be re-analyzed or if a sample with higher priority has to be analyzed, the rack containing that sample will be queued after all the others, which are already in the transportation path, therefore causing a significant delay in testing and retesting. Also, sample racks are typically engaged with a rail, for example, via a recess at the bottom of the racks as shown in FIG. 2b, such as to be able to follow the transportation path in a controlled manner, for example, without falling over or getting jammed. This constrain limits further the flexibility of such systems in handling sample racks.
Therefore, there is a need for a compact, simple and inexpensive sample rack handling unit that offers more flexibility and ease of use by comprising a rack onload section having an onload rail that enables a sideway engagement with a rack from a rack onload edge and a sideway disengagement by sliding the rack on an inclined onload rail side in the direction of the rack onload edge. In this way, it can be possible to load a rack or a plurality of racks at any position along the transportation path in the rack onload section, as well as to change the position of one or more racks or to remove one or more racks from any position, if for example, it is desired to replace a rack with another rack. At the same time, it can ensured that the racks can be smoothly transported longitudinally along the rail. Moreover, the shape and arrangement of the rail can allow an easy and ergonomic handling of the racks for a smooth and quick manual or automated operation both when engaging and when disengaging a rack.